The present invention relates to an apparatus and method for spraying water with abrasive particles mixed therein. More specifically, the present invention relates to a spray head, or nozzle, for mounting to a rotating lance for mixing abrasive particles with a flow of water for use in such operations as metal finishing.
A number of nozzles for spraying water and abrasive particles under pressure are available for use in metal finishing operations from a number of vendors. Such spray heads are, however, characterized by a number of disadvantages and limitations that decrease their utility. For instance, so far as is known, none of the spray heads that are currently available adequately mix the abrasive particles with the water. Instead, all known nozzles simply entrain the abrasive particles in the stream of water or introduce the abrasive particles into a cone of water that is spraying from the nozzle, thereby dispersing the abrasive particles in the cone of water. Either way, the ability of such spray heads to remove rust, lime scale, and paint and/or other coatings from a surface is compromised because the abrasive is not adequately mixed with the water in the spray. If the size of the spray cone is decreased so as to increase the ability of such spray heads to remove such surface characteristics from the metal, the resulting spray pattern is so small that the job of cleaning the metal is slowed to the point that economy suffers.
There is, therefore, a need for an improved nozzle for spraying abrasive particles in water, and it is an object of the present invention to provide such a nozzle.
It is also an object of the present invention to provide a nozzle for mixing water with abrasive particles for use in such operations as metal finishing.
Another object of the present invention is to provide a method for mixing abrasive particles with water before the water exits a nozzle in a spray.
Another object of the present invention is to provide an apparatus and method for efficient metal finishing operations.
Yet another object of the present invention is to provide an apparatus and method for focusing the mixture of water and abrasive sprayed by a nozzle.
Other objects, and the advantages, of the present invention will be made clear to those skilled in the art by the following description of the presently preferred embodiments thereof.
These objects are achieved by providing a nozzle for spraying abrasive particles mixed in water comprising a housing with a spindle rotatable in the housing having a passage therethrough for the flow of water, the axis of the first portion of the passage being approximately coincident with the rotational axis of the spindle and the second portion of the passage having an axis that is angled relative to the first portion of the passage. A focal tube is also rotatable in the housing and is provided with a bore therethrough for passing the flow of water from the spindle and out of the housing, the bore through the focal tube being angled relative to the first portion of the passsage through the spindle. An inlet is provided in the second, angled portion of the passage through the spindle for introducing abrasive particles into the flow of water passing through the spindle.
The present invention also provides a method for spraying abrasive particles in water comprising the steps of rotating a spindle having a passage therethrough for passing water in a housing, rotating a focal tube with the spindle, the focal tube having a bore therethrough for passing the water from said spindle out of the housing, and mixing abrasive particles with the water in an off-axis chamber in fluid communication with the passage through the spindle.